Can the need for soft tissue release in total knee replacement be predicted pre-operatively? A study based on surgical navigation.

INTRODUCTION: In complex and deformed knees, soft tissue release (STR) is required to obtain symmetry in the femorotibial gap. The objective of this study was to attempt to predict the need for soft tissue release using surgical navigation in total knee replacement (TKR). METHODS: Prospective and non-randomized study. One hundred thirty knees. At the start of navigation, an attempt was made to correct the femorotibial mechanical axis by applying force to the medial or lateral side of the knee (varus-valgus stress angle test). A gap balanced technique with computer-assisted surgery (CAS) was performed in all cases. The ligaments were tensioned, and using CAS visualization and control, progressive STR was performed in the medial or lateral side until a symmetry of the femorotibial gap was achieved. RESULTS: Eighty-two patients had a varus axis ≥ 3° and 38 had a valgus axis (P < 0.001). STR was performed under navigation control in 38.5% of cases, lateral release (LR) in 12 cases, and medial release (MR) in 38 cases. After performing the varus-valgus stress angle test (VVSAT), the axis of 0° could be restored at some point during the manoeuvre in 28 cases. STR was required in 44.6% of varus cases and 27% of valgus cases (P = 0.05). A significant relationship was found between the previous deformity and the need for MR (P < 0.001) or LR (P = 0.001). STR was more common in male patients (P = 0.002) and as obesity increased. CONCLUSION: This study shows that pre-operative factors favouring the need to perform STR in a TKR implant can be defined.

Computer-assisted surgery improves rotational positioning of the femoral component but not the tibial component in total knee arthroplasty.

PURPOSE: Computer-assisted surgery (CAS) may facilitate better positioning of total knee arthroplasty (TKA) along the coronal and lateral axes; however, there are doubts as to its usefulness in the rotational plane. METHODS: This is a prospective study of 95 TKAs comparing two groups: the CAS group and the standard equipment group. The series comprises 95 cases. A radiography of the lower limb and computer tomographies (CTs) of the femoral condylar region, the proximal end of the tibia and the ankle were performed to measure rotational angulation. A month after TKA surgery, the radiography and the CTs were repeated to analyze the position of the prosthetic components in the rotational plane. RESULTS: In the coronal axis, both CAS and mechanical technique improved femoro-tibial alignment, but when there are preexisting deformities ≥4°, CAS obtains better results. A strong correlation (R = 0.94, p = 0.001) was observed between the mean rotational axis measured with CT in the tibial plateau and that measured from the axis of the ankle. The mean initial femoral rotation of the complete series was 6.7° and 2.7° at 1-month follow-up (p < 0.001). In the standard instrumentation group, the femoral rotation went from 6.8° to 2.3°, whereas in the CAS group the femoral rotation went from 6.5° to 3.1° (p = 0.039), which is very close to the ideal 3° angle of external rotation. Tibial rotation changed by 5.28° for the entire patient population, but no differences were found when comparing CAS and standard instrumentation. CONCLUSION: CAS improves frontal alignment in TKA, especially in the presence of preoperative deformities. In the femoral component, navigation most closely replicated the ideal 3° external rotation of the femoral component, but tibial rotation did not differ when comparing CAS to standard instrumentation. LEVEL OF EVIDENCE: II.

Treatment of periprosthetic infections: an economic analysis.

This review summarizes the existing economic literature, assesses the value of current data, and presents procedures that are the less costly and more effective options for the treatment of periprosthetic infections of knee and hip. Optimizing antibiotic use in the prevention and treatment of periprosthetic infection, combined with systemic and behavioral changes in the operating room, the detection and treatment of high-risk patient groups, as well as the rational management of the existing infection by using the different procedures according to each particular case, could allow for improved outcomes and lead to the highest quality of life for patients and the lowest economic impact. Nevertheless, the cost-effectiveness of different interventions to treat periprosthetic infections remains unclear.

Relationship between radiological grading and clinical status in knee osteoarthritis. A multicentric study.

BACKGROUND: Controversy exists regarding the relationship between radiographic findings and clinical status in knee osteoarthritis. Although the surgical indication for total knee arthroplasty (TKA) should be based on pain, clinical status, and the deterioration of quality of life, the radiographic study is the most commonly used criterion for preoperative evaluation. The objective of this study is to find out the relationship between the Ahlbäck classification and clinical status in patients undergoing TKA. METHODS: 1329 protocols were collected from preoperative studies in four multicentric working groups (the Interax, Duracon, Scorpio, and Triathlon Spanish groups) in 30 Spanish hospitals. Mean age was 70.4 years (SD: 6.8; range: 35 to 98); 76.3% of patients were women. Patients entered the study whenever the surgeon found that medical treatment was insufficient to control pain and functional limitation. Data were collected using electronic Case Report Forms, and included Ahlbäck grading scores, Hospital for Special Surgery Knee Score (HSS), SF-12, and other clinical and epidemiologic variables. RESULTS: According to the Ahlbäck grading system, patients were divided as follows: 243 grade I (18.3%), 358 grade II (26.9%), 416 grade III (31.3%), 241 grade IV (18.1%), and 71 grade V (5.3%). As for HSS, the following scores were obtained: <60 points in 925 patients (69.6%), 60 to 69 points in 286 patients (21.5%), 70 to 84 points in 112 patients (8.4%) and 85 to 100 points in 6 patients (0.5%). Scores showed a statistically significant difference depending on Ahlbäck grade, with a clear tendency towards decrease in HSS scores as the Ahlbäck grade increases (p<0.001). However, the HSS score difference between Ahlbäck grades I and V was of 9.56 points only. Comparing the status of the patients at the start (1994) and at the end (2010) of the data collection process, we observed that patients who underwent surgery in the last years were older and showed a lower Ahlbäck grade. CONCLUSIONS: We found a relationship between Ahlbäck grading and the preoperative clinical score. The range of variability of the HSS score between the different Ahlbäck grades is small.

Spinal fusion achieves similar two-year improvement in HRQoL as total hip and total knee replacement. A prospective, multicentric and observational study.

INTRODUCTION: Total hip and knee arthroplasty (THA/TKA) are surgical procedures with proven benefits. Although the literature reports outcomes of fusion of the lumbar spine comparable to those of THA/TKA in general health-related quality-of-life (HRQoL) questionnaires, functional assessment is nevertheless needed for these results to be of use in clinical practice and management. Aim of our study was to prove that lumbar spinal fusion has similar if not better outcomes than THA/TKA using intervention-specific HRQoL questionnaires and functional assessment questionnaires. MATERIALS AND METHODS: Observational, ambispective, multicentre study of three cohorts undergoing lumbar spinal fusion (n = 115), THA (n = 119) and TKA (n = 253). Patients were evaluated using the Short-Form-12 (SF-12), Harris-Hip-Score, Hospital for Special Surgery Scale (HSS) and Oswestry Low Back Pain Disability questionnaires. A minimum follow-up of two years was conducted. RESULTS: The SF-12 showed significant improvement in all groups. The SF-12 physical component summary score indicated a more severe pre-operative status (p = 0.031) in the THA cohort. The mental component summary score indicated a less severe pre-operative status in the TKA cohort (p = 0.008) and greater post-operative improvement in the TKA and THA cohorts across follow-up (six months p = 0.021; one year p = 0.012; two years p = 0.042). Functional assessment indicated greater pre-operative disability in the THA group. At two years of follow-up, functional improvement according to the Harris, HSS and Oswestry questionnaires were 152.01%, 50.07% and 41.14% respectively. CONCLUSIONS: This study demonstrates that lumbar spinal fusion and total knee and hip arthroplasty are comparable in terms of functional improvement when thoroughly studied with health, quality-of-life and functional assessment questionnaires.

Computed tomography is not necessary to assess rotation of the femoral component in navigation-assisted total knee replacement.

Objective To demonstrate that postoperative computed tomography (CT) is not needed if navigation is used to determine the rotational position of the femoral component during total knee replacement (TKR). Methods Preoperative CT, navigational, and postoperative CT data of 70 TKR procedures were analysed. The correlation between the rotational angulation of the femur measured by CT and that measured by perioperative navigation was examined. The correlation between the femoral component rotation determined by navigation and that determined by CT was also assessed. Results The mean femoral rotation determined by navigation was 2.64° ± 4.34°, while that shown by CT was 6.43° ± 1.65°. Postoperative rotation of the femoral component shown by CT was 3.09° ± 2.71°, which was closely correlated with the angle obtained through the intraoperative transepicondylar axis by navigation (Pearson's R = 0.930). Conclusions Navigation can be used to collect the preoperative, intraoperative, and postoperative data and final position of the TKR. The rotation of the femoral component can be determined using navigation without the need for CT.

The concentrations of soluble vascular cell adhesion molecule-1 and lipids are independently associated with venous thromboembolism.

BACKGROUND AND OBJECTIVES: Venous thromboembolism (VTE) involves inflammation and a relation with dyslipidemia which remains controversial. The vascular cell adhesion molecule-1 (VCAM-1) is a ligand expressed by activated endothelium (and recruits leukocytes) whose soluble form (sVCAM-1) increases in atherosclerosis, severe hypertriglyceridemia or deep vein thrombosis (DVT) in acute phase. We analyzed the association between VTE (> 6 months after), sVCAM-1 and lipid concentrations. DESIGN AND METHODS: Case-control study involving 126 consecutive patients (aged 25-80 years, 49% males) and 125 controls of similar age and gender. RESULTS: The patients had a more unfavorable lipid profile than controls [higher triglycerides (p<0.001), LDLc/HDLc ratio (p<0.01) or total cholesterol (TC) (p=0.07)] and higher sVCAM-1 concentration (p<0.01) even adjusting for arterial diseases. VTE was associated with extreme values of TC, LDL-c, triglycerides (>P90) and HDL-c (P90) (OR=4.2)(p<0.0001). The sVCAM-1 values were age-related (r=0.26, p<0.001) but independent of lipid levels. Hazards ratios from five-fold to ten-fold appeared when combining the sVCAM-1 top quartile (>970 ng/mL) with TC >250 mg/dL or HDL-c <45 mg/dL (p<0.01) irrespective of thrombophilic status. Recurrent or severe VTE cases (pulmonary embolism or proximal DVT vs. distal DVT) showed higher sVCAM-1 values (p<0.05). All the associations weakened among females. In stepwise logistic regression, obesity (p<0.001), sVCAM-1 (p<0.001) and LDL-c (p=0.004) in men and sVCAM-1 (p=0.02) and triglycerides (p=0.04) in women retained their independent association. INTERPRETATION AND CONCLUSIONS: Although the exact mechanisms linking abnormal lipid and sVCAM-1 concentrations to VTE await clarification, both seem to be independently associated.

[Evaluation of the implementation of the FAPACAN programme to prevent cancer behavioral risk in primary care users in the North of Spain]. / Evaluación de la implementación del programa FAPACAN para prevenir el riesgo conductual de cáncer en usuarios de atención primaria del norte de España.

BACKGROUND: The evaluation of the process is an essential condition to correctly measure the impact of educational interventions on behaviour, its psychosocial determinants and the state of change, in the context of health promotion. The aim was to evaluate the quality of the implementation of the FAPACAN Programme, designed to prevent behavioural risk of cancer in Primary Care, and to improve its psychosocial determinants in the A.S.E. Model and the state of change according to Prochaska and DiClemente Theory. METHODS: The quality of implementation was measured by means of a visit to the health centre, by filling in a checklist 'in situ', and a phone survey with the patient. Centralisation and association measures were found (Pearson and Spearman's coefficient). A multiple regression model was obtained with the score made by the patient (range of 0 to 8) and the covariables: gender, age, level of education, locality and family history of cancer. RESULTS: The quality scores obtained oscillate between 72% and 81% of optimum quality. Significant differences were found owing to the administrator (better with fewer years of exercise) and the patient (better with higher level of study). CONCLUSIONS: In general, the quality of implementation was more than sufficient, in spite of the poor provision by the health system.

Metal presence in hair after metal-on-metal resurfacing arthroplasty.

The elevation of metal levels in serum and urine during post-operative follow-up is a frequent find following the implantation of certain models of metal-on-metal hip prostheses. Among 45 patients with the same resurfacing prostheses, chromium (Cr) and cobalt (Co) levels in serum and urine were determined at 3, 4, 5, and 6 years after surgery. In the same period, levels of Cr, Co and molibdene (Mo) in scalp hair were also measured. Mean Cr and Co levels in serum were 8.29 µg/L (SD 17.97) and 8.38 µg/L (SD 21.97), respectively, whereas in urine levels were 16.20 µg/L (SD SD 32.55) and 75.40 µg/L (SD 190.86), respectively. In hair, mean Cr level were 163.27 µg/g (SD 300.62), mean Co level 61.98 µg/g (SD 126.48), and Mo 31.36 µg/g (SD 37.86). A high concordance was observed between chromium-urine and chromium-serum and between cobalt-urine and cobalt-hair. A moderate concordance was present between cobalt-urine and cobalt-serum, and between cobalt-hair and cobalt-serum. Eleven patients required revision surgery, five of them due to metallosis and periarticular cyst. At 1 year after reintervention, analytics were performed again and the following decrease rates were found: 42.8% in Cr levels, 51.1% in Mo levels, and 90.3% in Co levels.

Economical analysis on prophylaxis, diagnosis, and treatment of periprosthetic infections.

The economic burden of periprosthetic infections is enormous, but the number of economic studies dealing with this issue is very scarce. This review tries to know the economic literature existing, assess the value of current data, and recognize the less costly and more effective procedures for prevention, diagnosis and treatment of periprosthetic infections. Forty five studies meeting the inclusion criteria and adhering to the quality criteria used were carefully analyzed to extract the economic data of relevance in evaluating the magnitude of problem and the more cost-effective solutions. However, because the heterogeneity and the low-quality of most of these studies meta-analytical technique has not been possible. Instead, the studies have been reviewed descriptively. Optimizing the antibiotic use in the prevention and treatment of periprosthetic infection, combined with systemic and behavioral changes in the operating room; detecting and treating the high-risk groups; a quick, simple, reliable, safe, and cost-effective diagnosis, and the rationale management of the instituted infection, specifically using the different procedures according to each particular case, could allow to improve outcomes and produce the highest quality of life for patients and the lowest economic impact. Nevertheless, the cost effectiveness of different interventions to prevent and to treat the periprosthetic infection remains unclear.

Total knee arthroplasty in the elderly. Is there an age limit?

The goal of this study was to compare the results of the total knee arthroplasty (TKA) in 2 study groups only differing by age. We have analyzed 218 TKA cases (138 women and 80 men) with at least 2 years follow-up. Mean age was 70 years (SD, 7.38 years; range, 43 to 98 years). An age cutoff point at 75 years defined the 2 study groups: 167 cases younger than 75 years and 51 older. Results were evaluated using the Hospital for Special Surgery Score. Mean score was raised from 53.43 (SD, 9.186) preoperatively to 85.57 (SD, 10.763) in 2 years follow-up (P < .001). The final score did not show significant differences between both groups (86.11 for the younger group and 83.8 for the older group). Differences in pain on walking, pain at rest, walk, range of motion, climbing stairs, transfer, muscle strength, or instability were not found between the patients younger and older than 75 years. We did not find any differences in TKA, functional score, or pain between the 2 studied groups.

Measurement of bone mineral density is possible with standard radiographs: a study involving total knee replacement.

BACKGROUND: Measured bone density correlates well with the mechanical properties of the bone. Our objective was to evaluate optical densitometry as a method of measuring the periprosthetic bone density of the tibial platform in total knee replacement using serial dual-energy X-ray absorptiometry (DXA) as the reference test. METHODS: 30 patients who underwent a cemented total knee replacement were followed up for over 2 years. Standard radiographs of the knee were obtained at 12 and 24 months. These were photographed with a digital camera and enhanced with image processing software. A DXA scan was performed at the same time as the reference method. 3 regions of interest were defined under the tibial plateau (medial, lateral and stem positions). RESULTS: After 24 months of follow-up there was a significant decrease in density in the 3 regions, both with the optical and DXA methods. The concordance between methods was studied using Bland and Altman plots, Cronbach's alpha and intraclass correlation coefficients resulted in values from 0.72 to 0.87, depending on the region and the follow-up time. INTERPRETATION: Quantification of optical density values with a standardized measurement system on conventional radiographs is a reliable and efficient method of determining the bone mineral density.